A pullulanase is a starch debranching enzyme, which can hydrolyze alpha-1,6 glucosidic bond of polysaccharides so that the amylose can be converted into amylopectin to the maximum extent. The pullulanase has very important application in the starch processing industry, and it can improve on a large scale the utilization rate and the production efficiency of the starch, and is relatively well applied to production of glucose syrup, maltose syrup and beer.
In the production of glucose, pullulanase and glucoamylase are used together for a saccharification process, and the yield of glucose is increased by reducing the content of the oligosaccharide by using the pullulanase, and the dosage of the glucoamylase can be reduced.
The pullulanase can also be used in the beer industry, it can be added in the saccharification or fermentation process to improve the fermentation capability of beer wort.
In 1961, Aerobacter aerogenes which can produce pullulanase was first found by people, and good enzymatic properties of the pullulanase were reported. Since then, a variety of microorganisms capable of producing pullulanase were found by researchers in various countries through extensive research, such as Bacillus Cereus var. Mycoides, Bacillus Acidopullulyticus, Bacillus Subtilis, and Clostridum Themosulfurogenes. But most of the strains for producing pullulanase at present have no industrial value. The present disclosure will provide a high-activity pullulanase by means of genetic engineering.